It is proposed to continue the study of the mechanisms of action of selected inhibitors of protein synthesis, such as cycloheximide, anisomycin and sparsomycin and how cells react in vivo to their effects. Special attention will be given to their use in the analysis of ribosome dynamics during acute liver cell injury and repair. It is also planned to compare and contrast the effects of two nucleotide trapping agents, ethionine and galactosamine. The former acts acutely predominantly by trapping liver adenosine and thereby producing an acute deficiency of ATP while the latter traps uracil derivatives and induces an acute deficiency of UTP.